<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .footer{
            height:300px;
            width:1000px;
            background: red;
            margin-top: 800px;
        }
    </style>
</head>

<body>
    <a href="#footer">锚点</a>
    <button id="btn">跳转到footer的位置</button>
    <div class="footer" id="footer"></div>
</body>
<script>
    var btn = document.getElementById("btn");
    btn.onclick=function(){
        location.hash = "#footer";
    }
</script>
</html>